The invention is directed to a worm drive for setting the angular position of vertical lamella or slat style blinds comprising a vertical axis or shaft arranged inside a slat carrier housing, this vertical axis or shaft carries a pinion torsionally connected thereto and has its end side joined to a slat, whereby a worm rotatable by a drive shaft via an inside profiling is in drive engagement with the pinion.
Vertical blinds generally serve as sun screen and/or viewing screen for windows. However, they can also be utilized for other purposes such as, for instance, for subdividing or compartmentalizing larger spaces. Their vertically arranged slats are generally composed of textile material and fashioned strip-shaped, each having at least their upper ends secured to a slat carrier and are generally pivotable around a middle longitudinal axis, whereby a common pivoting of all slat of a vertical blind can ensue with a common drive. The slat carriers are generally in a carrying rail and are displaceable along this rail with a drive.
In the open position wherein the window is not covered by the slat, the slat are moved together at one side to practically form a packet, whereby the slat are positioned parallel to one another.
The setting of the angular position of the individual slat, as was already mentioned, ensues with a common drive that generally has the form of a drive shaft that is in positive engagement with worms seated in the slat carrier housings. The vertical axis or shaft at which the slat is held carries a pinion that meshes with the worm, so that the angular position of the slat can be set via the rotation of the drive shaft.
In a known drive of this species, the worm has its two ends seated in the front and in the back wall of the slat carrier housing. For introducing the worm into the housing, the latter must first be spread with a tool. This is not only involved but also frequently leads to breakage of the housing. Over and above this, the bearing of the worm at two end pegs or flanges causes a deep structure of the slat carrier housing. This, in turn, has the disadvantageous consequence that a relatively thick slat packet arises in the open position, i.e., when the slats are brought together. This is undesirable assuming considerable dimensions, particularly given wide windows or large room dividers.
In view of this problem, the object of the invention is to design the worm drive of the species initially cited such that a simple assembly is enabled without the assistance of special tools and excluding the risk of breaking a housing. At the same time, the structural depth of the slat carrier housing should be reduced in order, particularly given a slat packet that is brought together, to reduce the extent thereof in the direction of the carrying rail.
This object is inventively achieved by the features recited in the characterization of the generic claim, whereby the features of the subclaims are referenced with respect to preferred developments of the worm drive of the invention.